This lesson follows the description of mechanical oscillating systems that have an object in periodic motion.
This lesson shows how such an object in periodic motion, and in contact with a medium, such as air, water, or a solid, may create waves in that medium.
Note:
This lesson will not address processes that effect wave motion, such as Reflection, Refraction, and Interference. These topics are covered in following lessons.
Opportunities to Learn:
As in the previous lesson, students first opportunity to learn is by hands-on experiment,
and the second is by analysis of what was observed, and the third, as an advanced portion, is to continue the introduction to the techniques of understanding a system by choosing simple but justifiable models to analyze.
Depth of Knowledge
Dok1 and Dok2
This lesson extends the concept of Harmonic Motion in a continuous material,
to examine wave motion, and gives students hands-on examples to work with,
and observe while varying certain parameters.
Students are asked to note which parameters caused changes in system behavior,
and to note the similarities and differences of the different example systems.
This is followed by a lecture in which the wave process observations are discussed and compared.
An optional advanced treatment uses simplifying assumptions to enable the analysis.
Prerequisite Knowledge
Harmonic Motion
Plans for Differentiating Instruction
As in previous lesson.
Accommodations and modifications
This lesson begins with laboratory exercises, which are intended to be done by small teams. The instructor may want to form teams in which a student with a special need may be teamed with students that can provide needed assistance.
Lab worksheets for data collection ordinarily start empty, with only required sections indicated, but customized sheets can be provided to give additional guidance.
Pre-Lab Readiness Test may be waived if the student will have assistance and direct supervision.
Environmental factors
none
Materials
Plastic cups and fishing line for a string telephone, and funnels and plastic tubing for a speaking tube.
Slinky (tm) springs to illustrate different types of wave motion.
Objectives:
Students will be able to
identify and explain the several modes of mechanical wave propagation.
explain why solids, liquids,or gases favor different modes of wave propagation.
explain properties of those materials that influence wave propagation
Instruction:
Opening:
String telephones and speaking tube telephone are set up. and have signs inviting students to try them.
Last time we learned about Simple Harmonic Motion.
This lesson shows how such an object in periodic motion, and in contact with a medium, such as air, water, or a solid, may create waves in that medium.
This lesson explains the fundamental difference between a system in periodic motion and a wave:
an oscillating system has an object in periodic motion about a fixed point, and (neglecting losses) it retains energy
a wave transfers motion from an object at one point to an object at a neighboring point, and thus transmits energy
This lesson shows that there are several types of mechanical wave possible:
surface waves in liquids,
transverse or shear waves in solids,
longitudinal or compression waves in solids, liquids or gases.
You will manipulate and observe examples of all types of mechanical waves.
Today we will use children's toys, a Slinky (tm) spring, a string telephone and a speaking tube,
and, if you are good, everyone's favorite, a Human Wave.
The Slinky needs no introduction, but I do have to ask you to be careful with it, use it as needed for the lab, and do not stretch it out of shape.
The string telephone usrs a string strectched between the bottoms of two open containers such as plastic cups.
Words spoken into one cup can be heard by someone listening at the other.
It is easy to understand the vibration of one cup pulling the string to cause vibration in the other.
The speaking tube uses a length of tubing with a funnel at each end.
Again words spoken into one may be heard at the other.
How can the air in the tube serve the same purpose of pulling on air at the other end?
The Human Wave also needs no introduction, but we hope to study several variations.
Again, I do have to ask you to be careful with it, use it as needed for the lab, and do not stretch it out of shape.
In other words, no fooling around.
Engagement:
First, I would like volunteers to try the string telephone.
What did you find for the string telephone?
What carries the sound?
What makes it work better?
Or worse?
Can it go around a corner? Are you sure?
Now, I would like volunteers to try the speaking tube.
What did you find for speaking tube?
What carries the sound?
What makes it work better?
Or worse?
Can it go around a corner? Are you sure?
So what was different? And why? Any ideas?
Sound waves in a string can be transverse (motion sideways to the string) or longitudinal (along the string).
According to Wikipedia In 1664–1665 Robert Hooke (of Hooke's law for springs) experimented with sound transmission through a stretched wire.
Now, I would like a volunteer to demonstrate a transverse wave with the Slinky. You can do that by wiggling one end from side to side, while the other end is attached to a firm support. Just give it one or two wiggles, so we can see what they do, without getting confused. You can do this on the lab bench, and we should all be able to see it.
Please remember the cautionary words.
Please do this with the Slinky stretched out at several different lengths
Also try it at several different wiggle rates.
Also at several different wiggle amplitudes.
OK, that was enough fun. What did we see?
Did anything affect the speed of the wave?
Did you notice a reflection?
((I'm thinking a string always becomes transverse even if you drive it by a longitudinal vibration. Is this true? We could find out by looking at the string with a stroble light and driving the string telephone with the same frequency sound. This could be an advanced question.))
Sound waves in air or water must be longitudinal, compression along the path, since without the spring like forces linking the neighboring molecules of a solid, it can not support sideways motion.
Now, I would like another volunteer to demonstrate a longitudinal wave with the Slinky.
You can do that by gathering together about a dozen turns, and then releasing your grip on them all at once.
Do this while the other end is attached to a firm support.
This will send one wave down the Slinky, so we can see without getting confused.
You can do this on the lab bench, and we should all be able to see it.
Please remember the cautionary words.
Please do this with the Slinky stretched out at several different lengths
Also try it at several different number of turns gathered together to start.
(There is no way to repeat this rapidly.)
OK, that was enough fun. What did we see?
Did anything affect the speed of the wave?
Did you notice a reflection?
Finally, since we have all been good, I would like you all to volunteer for a Human Wave.
We will first make a transverse wave, and then a longitudinal wave.
The question for both is, what determines the speed of the wave?
Assessment:
Students will be able to explain why each type of wave is or is not able to travel in solids, liquids, or gases.
For each type of wave, students will be able to explain how one or more parameters effects wave motion.
Students will be able to explain these effects qualitatively.
Lesson Plan
Lesson Title: Wave Creation and Propagation
State Standards: GLEs/GSEs
see Unit
National Standards:
see UnitContext of Lesson:
This lesson follows the description of mechanical oscillating systems that have an object in periodic motion.This lesson shows how such an object in periodic motion, and in contact with a medium, such as air, water, or a solid, may create waves in that medium.
Note:
This lesson will not address processes that effect wave motion, such as Reflection, Refraction, and Interference.These topics are covered in following lessons.
Opportunities to Learn:
As in the previous lesson, students first opportunity to learn is by hands-on experiment,
and the second is by analysis of what was observed, and the third, as an advanced portion, is to continue the introduction to the techniques of understanding a system by choosing simple but justifiable models to analyze.
Depth of Knowledge
Dok1 and Dok2
This lesson extends the concept of Harmonic Motion in a continuous material,
to examine wave motion, and gives students hands-on examples to work with,
and observe while varying certain parameters.
Students are asked to note which parameters caused changes in system behavior,
and to note the similarities and differences of the different example systems.
This is followed by a lecture in which the wave process observations are discussed and compared.
An optional advanced treatment uses simplifying assumptions to enable the analysis.
Prerequisite Knowledge
Harmonic Motion
Plans for Differentiating Instruction
As in previous lesson.
Accommodations and modifications
Environmental factors
none
Materials
Plastic cups and fishing line for a string telephone, and funnels and plastic tubing for a speaking tube.
Slinky (tm) springs to illustrate different types of wave motion.
Objectives:
Students will be able to
Instruction:
Opening:
String telephones and speaking tube telephone are set up. and have signs inviting students to try them.
Last time we learned about Simple Harmonic Motion.
This lesson shows how such an object in periodic motion, and in contact with a medium, such as air, water, or a solid, may create waves in that medium.
This lesson explains the fundamental difference between a system in periodic motion and a wave:
This lesson shows that there are several types of mechanical wave possible:
You will manipulate and observe examples of all types of mechanical waves.
Today we will use children's toys, a Slinky (tm) spring, a string telephone and a speaking tube,
and, if you are good, everyone's favorite, a Human Wave.
The Slinky needs no introduction, but I do have to ask you to be careful with it, use it as needed for the lab, and do not stretch it out of shape.
The string telephone usrs a string strectched between the bottoms of two open containers such as plastic cups.
Words spoken into one cup can be heard by someone listening at the other.
It is easy to understand the vibration of one cup pulling the string to cause vibration in the other.
The speaking tube uses a length of tubing with a funnel at each end.
Again words spoken into one may be heard at the other.
How can the air in the tube serve the same purpose of pulling on air at the other end?
The Human Wave also needs no introduction, but we hope to study several variations.
Again, I do have to ask you to be careful with it, use it as needed for the lab, and do not stretch it out of shape.
In other words, no fooling around.
Engagement:
First, I would like volunteers to try the string telephone.
What did you find for the string telephone?
Now, I would like volunteers to try the speaking tube.
What did you find for speaking tube?
So what was different? And why? Any ideas?
Sound waves in a string can be transverse (motion sideways to the string) or longitudinal (along the string).
According to Wikipedia In 1664–1665 Robert Hooke (of Hooke's law for springs) experimented with sound transmission through a stretched wire.
Now, I would like a volunteer to demonstrate a transverse wave with the Slinky. You can do that by wiggling one end from side to side, while the other end is attached to a firm support. Just give it one or two wiggles, so we can see what they do, without getting confused. You can do this on the lab bench, and we should all be able to see it.
Please remember the cautionary words.
Please do this with the Slinky stretched out at several different lengths
Also try it at several different wiggle rates.
Also at several different wiggle amplitudes.
OK, that was enough fun. What did we see?
- Did anything affect the speed of the wave?
- Did you notice a reflection?
((I'm thinking a string always becomes transverse even if you drive it by a longitudinal vibration. Is this true? We could find out by looking at the string with a stroble light and driving the string telephone with the same frequency sound. This could be an advanced question.))Sound waves in air or water must be longitudinal, compression along the path, since without the spring like forces linking the neighboring molecules of a solid, it can not support sideways motion.
Now, I would like another volunteer to demonstrate a longitudinal wave with the Slinky.
You can do that by gathering together about a dozen turns, and then releasing your grip on them all at once.
Do this while the other end is attached to a firm support.
This will send one wave down the Slinky, so we can see without getting confused.
You can do this on the lab bench, and we should all be able to see it.
Please remember the cautionary words.
Please do this with the Slinky stretched out at several different lengths
Also try it at several different number of turns gathered together to start.
(There is no way to repeat this rapidly.)
OK, that was enough fun. What did we see?
Finally, since we have all been good, I would like you all to volunteer for a Human Wave.
We will first make a transverse wave, and then a longitudinal wave.
The question for both is, what determines the speed of the wave?
Assessment:
Students will be able to explain why each type of wave is or is not able to travel in solids, liquids, or gases.
For each type of wave, students will be able to explain how one or more parameters effects wave motion.
Students will be able to explain these effects qualitatively.
Internet Resources
These are teacher resources.
String and Spring Demos Univ Northern Iowa
Human Wave Demonstration
Seismic Waves and the Slinky: A Guide for Teachers
Reflections
(only done after lesson is enacted)Student Work Sample 1 – Approaching Proficiency:
Student Work Sample 2 – Proficient:
Student Work Sample 3 – Exceeds Proficiency: